Telephone system



Dec.. 7 1926.

\ H. P. MAHONEY TELEPHQNE SYSTEM Fiied Nov. 25. 1922 Hal-Laney FatentedDet: 7, 1926.

kwam@ unirse srarss PATENT ortica.,

HARRY 1. MAHONEY, or OAK PARK. rumors. Assiettes, BY Mnsnnassrsnrinnrs,

TO AUTOMATIC ELECTRIC-INC., OF CHICAGO, ILLINOIS, A CORPORATION OFDELA-` WARE.

TELEPHCNE SYSTEM. l

My invention relates in general to telephone systems in whichconnections may be established through the medium of subscribercontrolled selector and lconnector switches, or in ivhichvan operator isdepended upon to manually interconnect the subscribers circuits forpurposes of conversation; but is more particularly concerned with thetransmission of lire, burglar, or other alarm signals: and the object ofthe invention maybe said to be; broadly. the provision of new andyimproved `auxiliary appa ratus for use in connection with a telephonesystem. f

It is sometimes desirable to associate an auxiliary service ot' sometype with a tele-4 phone system. so asto lutilize, the telephone linesand other apparatus ofthe telephone system for the auxiliary service. Asis Well knoivn, the ordinalv telephone lines of an exchange are idle agreat. part of the day and practically all of the night. and a largeproportion ofthe capital invested in the telephone plant is thereforeidle and incapable of earning revenue: but by combining an auxiliaryservice with the telephone service an additional earning capacit)v isthus imparted to the capitalinvestcd in the plant.

In 'the preferred embodimentvofmv yinvention I employv in connectionwith acommon battery telephone exchange means bv which a subscriber.when desiring 'protection.`ma v cause a high resistance to be connected.between the negative side of the telephone line and ground at hissubstation. This resistance thereupon allows sufficient current to flowtopreserve" the normal condition of the alarm receiving apparatus. rThealarm receiving apparatusconsists, in part. ot tivo relays connected inseries. and in circuit with the high resistance at the substation. (lnerelay being comparatinely high in resistance is designed to hecontinuously operated ivhen in circuit ivith the above mentionedresistance. The second relay being low in resistance does not operateWhen in cire cuit With the above menticne'l resistance. but is sodesigned that it will operate should the said resistance become shortcircuited.

It is thus seen that mv invention comprises the combination of a normaltelcphone circuit with an alarm circuit, in which there is acomparatively weak but continuous current ow during the time that agiven substationis under protection,l this current flott7 serving topreserve the normal conditionof the alarm receiving apparatus Then thiscurrent is interi'upted as the resultA` for instance, of the opening ofa door, the breaking of a Window or the operation of a fusible link, thecomparatively high re-y sistance relay in the alarm receiving apparatuswill deenergize and thus bring in the alarm. If. in an attempt to outwitthe alarm system, the high resistance 'at the substation .becomes shortcircuited the increased cur-- rent flou' will be such as to operate thelow resistance relay in the alarm receiving'apparatus. thuis bringing inthe alarm.4

Referring to the drawings. Figs. l and 2 are circuit diagrams ofsufficient of the apparatus to illustrate the preferred form of theinvention, Fig. l discloses the equipment pertaining to anautomatictelephone switchboard Wherewith` to establish a connection between acalling substation A and a called substation A', while Fig. 2 shows theauX- iliary alarm equipment. In View of the fact that much of thetelephone apparatus is Well known the detailed circuits have in someinstances y been omitted and the apparatus l f merely indicated inschematic form. .The line circuits, however7 have been shown complete. lw l The apparatus shown may be briefly described as folloivs: Thesubstation A is an kautomatic substation or telephone of Well knowntype. In close proximity thereto is mounted the locking key K. thisbeing the key which isoperated when the subscriber desires protection.It is to be assumed that the ivatchmans liack J is mounted in a secretplace outside the premises. its location being known only to thepatrolman on the beat. The, substation is connected with the centralotiice bv. the line comprising conductors l1v and 12. At the exchanget-hisline terminates in the individual line or trunk selecting switchindicated by thereference character C. This individual switch is of aWell known type. the only change being in the manner in which positiveand negative battery .is normally fed to the line. The line 'switch Chas access in the usual `manner to a plurality of first selectors,suchas thel selector E. Thevtirst selectors have access in the usualmannerto a plurality of second selector sivitchcs, such as the selectorE. The

mounted upon the alarm board. This equip ment will consist of a lockingkey K2, -a guard lamp L, an alarm lamp L and a multiple line jack J2,for each line which is to be given protection. provided in order thatthe attendant may supervise a line under protectlon. Ad]acent to eachline jack, such as the jack J2, wlll be placed a designation stripshowing the number of the associated telephone line and the hours duringwhich this line is to be under; protection. For instance, thedesignation might be as follows: Telephone No. 2829. 'Protect from 5:30p. m. to 9-:00 a. m.-K.Y.W. i

It is thought that the operation of theauxiliary apparatus can best beexplained by first describing the operations which take place when thesubscriber at substation A calls the subscriberat substation A. When thereceiver at substation A is removed 'a circuit is closed through theline relay 130i" line switch C. This circuit may be traced from ground Gat the line switch C, through the line relay 13, through the cut oli2springs 14 and 15, line conductor 12, through the substation A, lineconductor 11, through the cut oli" springs 17 and 18, through the lowresistance relay 20, through the comparatively high resistance relay 21,to negative battery. The relays 20 and 21 will energize over 'thiscircuit, but'their operation at this time is without eli'ect. The vlinerelay 13 will energize'over the above-traced circuit and Will close a'circuitthrough the operating winding 22 of the line switch C, whereuponthe line switch C is operated in the usual manner tol extend theconnection to an idle first selector switch;l As isA well known, the cutoli springs are now in an operated position, thus removing relays 13, 20and 2l from the calling line. Successive operations of the dial nowcause the operation of the selected first selector, a second selectorand a connector. Let us assume that the called line is idle, and thatthe connector has caused the cut ofi' relay 23 of the line switch C tobecame operated. The operation of the cut oit| relay 23 resulted in theremoval of relays 24, 25 and 26 from the called line. The calledsubstation is now being signalled, and when the called party answers,conversation may proceed as desired. Vhen the subscribers are throughthey will both replace their receivers, where- A cord circuit B is u onthe release of theapparatus will take p ace in the usual manner. Therelays 13, 2O and 21 will again be connected to the calling line, whilerelays 24, 25 and 26 will.

again be connected to the called line. A

The auxiliary service which I show in -connection with this invention isJfor fire,

burglar or other alarm service and will how be explained-in detail. Wemay assume that the substation A shown on the drawing is lthe substationreferred to by the following designation on'the ala-rm board, TelephoneNo. 2829., Protect from 5:30 p. m. to 9:00 a.m. K. Y. W;. lThesubscriber at substal tion A Will operate thelocking key Ksometime'previous to 5:30p. 1n. When-this key is'operated thecomparativelyv high resist-4 ance relay 21 at' the central-ottico willbe come energized over acircuit which may be traced from ground G2 atthe calling sub-v lance relay 21, to negative battery. The comparativelyhigh resistance relay 21 will energize over the above tracedcircuit,`but is without effect at this time. Theresistance 27 is soadjusted that the low resistance relay 20 will not operate when inseries with it.

Promptly at v5 :30 p. 1n. the attendant will go over the alarm board andoperate the locking key associated with each line that is to go under'protection at 5:30 p. m. l/Vhen the keyK2 is operated the guard lamp Lwill light asan indication that the key K at the associated substationhas been operated, and that t-he line is now under protection. Thecircuit may be traced from ground G3, through locking key K2, springs 29and 30, through guard lamp L, to negative battery. Promptly at 9:00 a.m. the attendant will go over the alarm board and restore the. lockingkey associated with each line that is to go ofi' protection at thathour. When the. key K2 is restored the lamp L will be extinguished,indicating that the asl sociated line is no longer under protection. Thesubscriber, entering his place of business sometime after 9:00 a. m.,will restore kev K, thus causing the deenergization of relay 21. Theauxiliary apparatus is now at normal and will remain so until the lineagain goes under protection at 5:30 p. m.

The operation resulting from the opening of one of the conductorsrepresented by the reference ligure 28 will now be explained, it beingassumed that the vsubstation A is under protection. It is to beunderstood that the conductors represented by the figure 28 may vary innumber depending upon local requirements; and that these conductors mayconsist of a pair of contacts designed to be separated by the opening ofa door or window; a fragile conductor designed to be opened by thebreaking of a pane of glass; a conductor .designed to fuse and open thecircuit at a predetermined temperature; a combination of the above, orin fact, any device known t0 the art whereby a closed circuit alarmsystem may be opened. As may be seen from the circuit, the opening ofany conductor in the series will cause the deenergization of themoderately hi h resistance relay 21, as av result of which t e alarmlamp L will light. The circuitmay be traced from ground G3, through keyK2, through springs 29 and 31, through alarm lamp L, through pilot relay32, to negative battery. The pilot relay will energize over this circuitandbring in both a visual and an audible alarm. The attendant, seeingthe lamp L lighted, will insert the plug P into the jack J2. Thesecondary and tertiary windings of the induction coil, in series withthe operators head set, are now bridgedacross line conductorsv 11 and12. This is a standard monitoring circuit and allows the operator tolisten in on the line. The operator then depresses the locking key K,which causes the cut oi relay 33 of the y yline switch C to operate,thereby removing .relays 13, 20 and 21 from the line. As the line is nowclear at the line switch C the op-,

' erator may depress the key K6 and connect l to outwit the alarmsystemb the line to a testing circuit. After completing the test theoperator will dispatch a patrolman to the premises to make aninvestigation.

The operation resulting from an attempt grounding the line conductor11'will now e explained,

it beingl assumed that the substation A is under protection. Whenconductor 11 is grounded, as at G4, the low resistance relay 20 willenergize and cause the alarm lamp L to light. The circuit may be tracedfrom ground at G4, over line conductor 11,

i through cut ott springs 17 and 18, through the low resistance relay20, through the moderately high f resistance relay 21, to negativebattery. The increased circuit llow will of course have no eti'ect uponrelay 21, as that relay is already in an operated position. Theincreased circuit flow will, however, cause the low resistance relay 2Oto operate, and as a result the alarm lamp L will be lighted. Thecircuit may be traced from ground G3, through locking key K2, throughsprings 34 and 35, through the alarm lamp L', through pilot relay 32, tonegative battery. The pilot relay will energize over this circuit andbring in both a visual and an audible alarm. The attendant seeing thelamp L lighted will insert the plug P into the jack J2, the procedurebeing the same asexplained in the preceding paragraph.

The operation resulting from an attempt to make a telephone call at astation under protection will now be explained, it being assumed thatsubstation A is under protection. The preferred operation would be thatin which the subscriber first restoredV the second case because of theopening ot its circuit at the cut oii springs 17 an The deenergizati onof the relay 21 will cause the alarm lamp L to light and attract theattention ot the attendant in the usual manner. The attendant thereuponinserts the plug P in the jack J2. As previously explained the cordcircuit B 1s normally a monitoring circuit, which allows the attendantto listen in on the connection without interfering with the dialling orotherwise affecting the telephone connection. The attendant will nowdepress the key K5 which closes the primary circuit of the inductioncoil, removes the tertiary winding, and in fact changes the cord circuitB into a standard operators talking circuit. The operator will nowchallenge the calling party, and if the password K. Y. W. is given, theattendant may assume that the call is a legitimate one being made by thesubscriber at substation A, the password for each station being the codeshown upon the designation strip, associated with the line in question,at the alarm board. If the calling party cannot give the password theattendant will send a patrolrnan to make an investigation of thepremises. If the call is a legitimate one the attendant will remove theplug P from the jack J 2, the connection being supervised by the alarmlamp L which will remain lighted until the calling subscriber restoreshis receiver to the switchhook land again depressesthe key K.

The operation in connection with the watchmans jack J will now beexplained, it being assumed that the substation A is under protection.The patrolman on the beat will call in at stated intervals by insertingthe plug associated with his hand telephone into the secret watchmansjack mounted outside thc premises ot the subscriber. `When the patrolmaninserts a plug info the jack J the associated line switch Utl lll)

C will operate in the usual manner, there-A i It is to be noted that thejackJ is connected to the line onlywhen thekey K is in an operatingposition, and therefore, the watchmans jack is operative only when thesubstation is under protection. "I

The operation required when a line under protection is called fromanother telephone will now be explained, it being assumed thatthesubstation A is under protection. When substation A is called theconnector H will cause the operation of the cut olf relay 23 of the lineswitch C', and as a result relay 25 Will deenergize and cause the alarmlamp L3 to light. The attendant thereupon will place the plug P in thejack J3, 'operating the key K5 to'cut olf the ring and to allow him Vtotalk to the calling subscriber. The 'attendant will give the callingsubscriber such information as may be desired and, it the callingsubscriber does not release promptly, the alarm board attendant will getin touch with "the switchboard attendant and request him :to take downthe connection standing on the line to which substation A is connected.This provision is made in order that a calling subscriber cannotinnocently or maliciously render inoperative the alarm service of acalled line.

The apparatus represented in Fig. 2 may be, and preferably is,ilocatedin a separate room from the switchboard at the exchange and isv 'lookedafter by an entirely different set of attendants. In other words, thealarm apparatus may be separate and distinct and handled separately fromthe telephone exchange apparatus. This method of interpolating auxiliaryapparatus in telephone lines is very readily accomplished in eitherexisting or contemplated vexchanges without deviation from establishedpractice in their installation. and operation. 1

It is evident that one skilled in the art may utilize my invention inother systems than that shown Without departing from its spirit,

vand I therefore do not wish to limit myself to the specific structureillustrated and devScribed.

The object and scope of the invention having been described, what isconsidered to be new and what it is desired to have protected by LettersPatent Will be pointed out more specically in the appended claims.

What I claim is:

1. In an alarm system, -a closed circuit connecting a subscriberspremises with a central station, a resistance and a plurality ofconductors included in said circuit at the subscribers premises, saidconductors adapted to be broken by any agency against which the alarm isprovided, a normally energized relay in said .circuit at said stationadapted to deenergize if one of said conductors is broken, a normallydeenergized relay in said circuit in series with said first relay andadapted to energize if said resistance is short circuited, and an alarmoperated by the deenergization of said first relay or the energizationof said second relay.

2. In a combined telephone and alarm system, a subscribers telephoneline, means for extending connections to or from said line to includesaid line in talking circuits with other subscribersy lines, an alarmcircuit superimposed on said first line including protective devices, analarm at the exchange.l and responsive Vdevices for actuating said alarmin case said circuit is altered Aat the subscribers station and wheneversaid line is calling or is being called. p

3. In a combined telephone and alarm system, a subscribers telephoneline, means for extendin y to inclu e said line in talking circuits withother` subscribers lines, an alarm circuit superimposed on said firstline, a normally energized relay at the exchange included in saidcircuit and adapted to deenergize it the circuit is broken at thesubscribers station,

an alarm operated when said relay is deenergized, and a cut 0E relay foropening said circuit whenever said first line is calling or is beingcalled.

' 4. In a combined telephone and alarm system, a subscribers telephoneline, means for extending connections to or from said line to includesaid line in talking circuits with other subscribers lines, a normallyinoperative alarm system including a circuit superimposed on said line,and manually operable devices at the subscribers station and at theexchange co-operating to render the alarm system operative to protectthe subscribers premises, said manually operable device at the stationclosing said circuit continuously.

5. In a combined telephone and alarm system, ya subscribers telephoneline, means for extending connections to or from said line to includesaid line in talking circuits with other subscribers lines, an alarmcircuit superimposed on said line and normally open at the subscribersend thereof, a local alarmcircuit at the exchange also normally open,and devices at the subscribervs station and at thc exchange,respectively, for closing said circuits at a prearranged time Withoutoperating the alarm in order to place the v subscriber-s premise; underprotection, and

means for thereafter operating said alarm. 6. In a combined telephoneand alarm systelu, a subscriber?l telephone line, means for extendingconnections to or from said line,

a normally inoperative alarm circuit super-4 imposed on said liuc,manually operable devices on the liuc at the subscribers station and atthe exchange co-operating to render the alarm system operative, andadditional devices in said circuit at the subscribers station forcontrolling said circuit to operate an alarm.

connections to or from said line i Looms; Y- l 8 7. In a combinedtelephone and alarm system, a subscribers telephone line, means forextending connections to or from said line to include said line intalking circuits with other subscribers lines, an alarm circuitsuperimposed on only one side of said first line, an alarm at theexchange, and devices res onsive to a call to or from said first line anresponsive to an alteration of the circuit of said line to actuate saidalarm.

8. -In a combined telephone and alarm s stem, a subscribers linecircuit, talking 1nstrumentalities on said line and means for connectingthem in circuit with the line, an auxiliary circuit including said'subscribers line and alarm devices at the exchange, means for renderingsaid circuit eiective, a signal at the exchan e to indicate that theauxiliary circuit has geen rendered effective, and means at thesubstation for operating an alarm at the exchange over said circuit.

9. In a combined telephone andalarm system, a subscribers line, meansfor extending connections to or from said line, an auxiliary alarmcircuit including said line and signalling devices at the exchange,means at the station on the line for rendering said auxiliary circuiteffective, means at the substation for operating an alarm at theexchange over said circuit, and means at the exchange for operating analarm over said p ircuit when a call is made to or from said 10. In acombined telephone and alarm system, a subscribers telephone line, meansfor extending connections to or from said line to include said line intalkin circuits with other subscribers lines, an a arm circuitsuperimposed on only one side of said first line, an alarm at theexchange, manually operable devices on the line at said subscribersstation and at the exchange, cooperating to render the alarm systemoperative, and .devices responsive to a call to or from said line andresponsive to an altera-V tion of the circuit at the subscribers stationto actuate said alarm after the said manual- 1y operable devices havebeen operated.

In Witness'whereof, I hereunto subscribe by name this 20th day ofNovember, A. D.

HARRY P. MAHONEY.

